A solid catalyst that includes a transition metal catalyst component (e.g., titanium) and a main group metal catalyst component (e.g., aluminum) has been widely known as an olefin polymerization catalyst.
An olefin polymerization catalyst that utilizes a magnesium compound as a support exhibits remarkably improved polymerization activity. A polymer that exhibits high stereoregularity can be produced from an α-olefin having 3 or more carbon atoms by adding an electron donor such as an ester compound to the catalyst.
For example, Patent Literature 1 (JP-A-57-63310) discloses a method that polymerizes propylene using a solid titanium catalyst component that supports an electron donor such as a phthalic acid ester, an organoaluminum compound (co-catalyst), and an organosilicon compound that includes at least one Si—O—C linkage. A number of pieces of literature including Patent Literature 1 disclose a method for producing a polymer having high stereoregularity in high yield using a phthalic acid ester as an electron donor compound.
However, di-n-butyl phthalate and benzylbutyl phthalate (i.e., phthalic acid ester) are designated as substances of very high concern (SVHC) specified by Registration, Evaluation, Authorization and Restriction of Chemicals (REACH), and a catalyst system that is not so designated has been desired from the viewpoint of a reduction in environmental load.
A solid catalyst component that utilizes a succinic acid ester, a maleic acid ester, a malonic acid ester, a diether, or the like (that does not fall under the SVHC) as an electron donor compound is known.